DC biasing audio signal

Posted on Feb 6, 2014

My audio source will be a Line Level Audio -2V to +2V AC passed through a 220uF coupling cap and then a low pass filter(RC, 2 pole). The signal will be read by an ADC another one that i have seen is I don`t quite understand this FET-BJT preamp circuit And the schematic is for a pre-amp, and there are 2 versions and both add a bias. using the second one looks like it will work best for my

Click here to download the full size of the above Circuit.

application, using something like this- is there any other improvements I can make other then Stable Vref/power rails. The signal is going to be read by an ADC, for a BPM counter(beats per min) And Kellenjb you are correct coupling cap and not decoupling - fixed jsolarski May 18 `11 at 12:31 As a note: I use the first solution with no problems but my circuit is definitely not a high fidelity one as it is on a model aircraft with lots of other noise (motors, servo, wind etc. ) Thomas O May 18 `11 at 16:11 Don`t use the first circuit. Any noise or spikes on the power supply will be mixed with your signal. Because the bias point is connected directly to the signal, you can`t filter out power supply noise without also filtering out the signal. Do use the second circuit. It produces a mid-point voltage that is tightly coupled to ground, so the DC component is half the supply, but the AC component (noise and spikes) is filtered out by the capacitor. That`s not a complete circuit, though, you still need to connect it to your signal. The output is the same as the input, just shifted upward by 2. 5 V. The resistor on the input ensures that the input side of the capacitor is at 0 VDC, to prevent pops during connection. The resistor on the output side of the AC coupling cap biases that side to the DC bias voltage. If your circuit already has a clean, low impedance DC bias voltage source, connect to that. Otherwise, you can use circuit...

Visit page

Leave Comment

characters left:

Related Circuits

USART + Serial Comm with PC

Create simple Hello world example of serial comm to a PC using microcontroller USART.

BBC Micro Model B and a plume of acrid smoke

So, after yesterday`s post about The Demon Machine I decided it would be fun to play around with the BBC Micro Model B and so I plugged it in and powered up. The familiar two-tone boot sound played...

Arduino LED Dimmer

First thing`s first, what software to use I went with CadSoft Eagle primarily because there are lots of tutorials out there covering it, and that seemed like a good place to start. Once I...

usb controlled rgb led

The article on my RGB LED fader has been one of the most-visited articles on this blog. Since posting it, I`ve designed and built another microcontroller-based RGB LED project, this time...

Circuits

In order to avoid any soldering mistakes, I asked students to place all there resistors in the board first, and once I checked them, they could solder away. Capacitors were next, then LEDs then...

NDH2K13 Quals

UKDM Honda DC2 rear fog lamp to an RSX

This guide will show you how to install an EDM/UKDM Honda Integra DC2 rear fog light on your 05-06 Acura RSX.

series robot circuit

For our second build in the Make It Last Build Series, we`re constructing a robotic plant. This week, we`re going to put together the brains of the machine, which we will use in the coming weeks to...

New Circuits

Zero consumption Anti-theft High power Code Switch for E-Bike Batteries

This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
Ultrasonic distance finder circuit

The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Simple Metal detector circuit with CD4030

Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Fully automatic watering circuit for flower pots

Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
Simple deep searching metal detector circuit

The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
Sub-Harmonic Bass Converter for Electric Guitars

The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
Echo Depth Sounding Sonar for Boats

In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
100W HiFi Audio Amplifier Circuit

This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
Plant-Pot Water Level Indicator Circuit

A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....

Create NOW your QR MENU for your Restaurant / Hotel / Bar / Caffe,

Comprehensive ordering/paying features. fully personalized to suit your Business.

Update Anytime! Easy and Simple!

Popular Circuits

ac I need help matching parts

I want to use a picMicro 5v microcontroller combined with the figure 10 circuit from Link1 (Shown...

heroine clock

This 6" x 18" clock needs 52 light sources. It may one day allow humans to know the time without...

electronic circuit breaker

A circuit breaker is an automatically-operated electrical switch designed to protect an...

Darkroom Timer v2.0A for PCB Exposure Box

This is an improved version of the Darkroom Timer originally created by Stan Ockers (1999). Some...

Vacuum Tube Amplifier Pioneer SM-83 Restoration

After restoring my Fisher 400, I could not let my smart head and creative hands rest. So I have...